Technical Field
The present invention relates to semiconductor processing and devices, and more particularly to devices and methods employing multiple threshold voltages on a same wafer or chip.
Description of the Related Art
Multiple threshold voltage (multi-Vt) technology is needed for obtaining performance benefits arising out of transistor scaling without paying a severe penalty in terms of leakage power consumption. Multi-Vt devices can be fabricated through changes to different parts of a wafer. These parts may include changes to a gate oxide material (including thickness); changes to a work function (WF) metal in a gate conductor; and dopant concentration changes to name a few. All of these changes involve significant process complexity. The process complexity associated with these changes is further increased with the use of fin field effect transistor (finFET) technology. The proposed processes provide a simpler method to fabricate multi-Vt devices, thus providing significant benefit in terms of reduced process complexity.